Apparatus for the manufacture of transparent sheets of pyroxyline



(No Model.)

A E. N. TODD.

APPARATUS FOR THE MANUFACTURE OF TRANSPARENT SHEETS 0P YRQXYLINP.

No. 483,701. Patented Oct. 4, 1892.

6%QA. 6 A Q AGW, ATT'Y.

UNITED STATES PATENT OFFICE.

EDMUND N. TODD, OF NEWARK, NEW' JERSEY.

APPARATUS FOR THE MANUFACTURE OF TRANSPARENT SHEETS OF PYROXYLINE.

SPECIFICATION forming part of Letters Patent No. 483,701, dated October4, 1892.

Application filed December 9, 1890. Serial No. 374.023. (No model.)

To aZZ whom it may concern:

Be it known that I, EDMUND N. Tom, a citizen of the United States,residing at Newark, in the county of Essex and State of New J ersey,have invented certain new and useful Improvements in Apparatus for theManufacture of Transparent Sheets of Pyroxyline; and I do hereby declarethe following to be a full, clear, and exact description of theinvention, such as will enable others skilled in the art to which itappertains to make and use the same, reference being had to theaccompanying drawings, and to letters of reference marked thereon, whichform a part of this specification.

The present invention relates to improvements in an apparatus for themanufacture of thin, transparent, and flexible sheets of nitro-celluloseand other compounds of pyroxyline. I

The invention relates more particularly to the improved form of platesemployed, which are spirally wound, instead of the straight plates usedin my process of manufacture of such sheets of nitro-cellulose, &c.,described in my patent issued May 27, 1890, and numbered 428,654.

By the use of my improved plates or coils I am enabled to produceperfect and flexible sheets of nitro-cellulose of any desired length,which is of the greatest importance when such sheets are to be used forphotographic purposes. By this arrangement the sheet, which is of muchgreater length, is also of uniform thickness throughout, which is veryessential, at the same time being free from air-bubbles, which renderthe sheets of little value. In order to produce such sheets, I proposeto employ a varnish or thick collodion or solution of pyroxyline ornitrocellulose, which consists of soluble pyroxyline or nitro-cellulosedissolved in the various of the well-known solvents mixed with thevarious well-known menstrua.

The improved apparatus which I desire to use in the manufacture of thin,flexible, and transparent sheets of nitrocellulose or pyroxyline forphotographic purposes is illustrated in the accompanying sheet ofdrawings, in which similar'letters of reference are employed to indicatecorresponding parts in each of the several views.

In the drawings, Figure 1 is a vertical section of the apparatus. Fig. 2is a top view of the same with the cover removed, both viewsillustrating the manner of supporting the spirally-shaped plates orcoils. Fig. 3 is a vertical section of the upper part of said plate,illustrating the manner of placing a frame thereon provided withdownwardly projecting teats or lugs for holding and separating thespiralsurfaces of the plate or coil, whereby the proper spaces aremaintained between the surfaces.

In the views, a is a tank or receptacle of any desired construction,provided at the top thereof with a removable cover b and in its bottom,which is preferably inclined, as shown, with a spigot or valve 0.YVithin said tank or receptacle, near the bottom thereof, is placed orsecured upon suitable shoulders at, and which may be secured in anyother convenient manner, a partition cl of wire-netting, in which themeshes are arranged far enough apart so as not to obstruct the flow ofthe dissolved solution of pyroxyline or nitro-cellulose through thesame. Upon this partition d is placed a spirally-formed plate or coil 6,which is preferably made of thin metal plated with silver, for suchplates are not destroyed by the chemical action of the solventsemployed, and, furthermore, the sheet of nitro-cellulose or pyroXylinecan be readily removed from such silver-plated plates and without anyblemishes whatever. Of course, if desirable, the plate 6 can besuspended within the tank a in any other convenient manner, as will beunderstood.

As is clearly illustrated in Figs. 1, 2, and

3, when the plate 6 has been placed upon the partition (1, in order tokeep the spiral surfaces of the said plate the proper distances apartand to prevent the capillary attraction of the solution with thesurfaces of the plate from drawing the said surfaces toward one another,I have placed upon the upper part of the plate 6 a frame f, made ofcross-pieces secured together and provided with downwardly-projectinglugs f which engage with the upper edges of the spiral plate and thereby holds said spiral surfaces of the plate in their proper positions.Then the spirallyformed plate or coil 6 has been placed within thereceptacle or tank a, the solution of pyroxyline or nitro-cellulose orother like solut-ion is poured into the receptacle until the plate 6 isalmost entirely immersed in the solution of collodion or varnish, andthe same is then allowed to remain quiet until all the air has escapedand all air-bubbles have disappeared and the liquid solution remainsquiet. The cover 5 is then placed upon the receptacle and the liquid isallowed to remain at rest for a time. As will be noticed from Fig. l,the cover 6 is provided with an outlet or pipe g, through which alldisagreeable odors and gases and fumes are passed off withoutendangering the health of the operator. WV hen the liquid collodion orvarnish or solution of pyroxyline has remained within the tank therequired time to thoroughly form an even coating upon the spiralsurfaces of the plate e, the spigot or valve in the bottom is opened andthe liquid is allowed to flow slowly into a receptacle h, placed beneaththe spigot, where the solution is stored until required for the nextprocess of again coating the plate 6. When the liquid solution has beengradually withdrawn until the tank has been emptied, I accomplish, as anew result, the production of a thin and even coating on the plate,which coating is free from any blemishes or air-bubbles, the solvents,as the solution is being gradually withdrawn and the level of thesolution slowly becoming lower and lower in that small part of thesolution adhering to both surfaces of the plate 6 evaporating, andthereby leaving two very thin films of nitrocellulose adhering to thesurfaces of the plate, which as they become exposed dry quickly andevenly. When all the liquid has been drawn off from the receptacle ortank, the coated plate of nitro-cellulose or pyroXyline is allowed toremain within the receptacle for a time until the coating has becomethoroughly dry, free from dust, thereby resulting in the production oftwo very long, even, and perfect films of nitrocellulose or pyroxylineon said spiral plate 6. These films are removed from the spiral plate orcoil when the latter has been taken from the receptacle a by scratchingor scraping the upper and lower edges of the plate with a knife or othersharp tool and placing the plate successively into hot and cold water,or vice versa, whereby said plate is expanded and contracted, and thefilms being loose at both ends of the plate, drop therefrom in two longand perfect sheets. By this device perfect sheets of any length andwidth can be made with ease. When the films of nitro-cellulose orpyroxyline have been removed from the plate 6, the latter is againreturned to the tank and is ready for the next process. Of course itwill be evident that the construction of the apparatus may be variedwithout departing from the scope of the present invention, and Itherefore do not wish to be understood as limiting myself strictly tothe construction herein shown, and the plate 8 can be plated with anydesirable metal suitable for this purpose, or may be made of any metalor glass.

. Having thus described my invention, what I claim is'- 1. Theherein-described apparatus for the manufacture of thin transparentsheets of nitro-cellulose or pyroxyline, which consists of a suitabletank provided with a spigot or valve having a wire-netting partition anda spirally-formed plate or coil arranged thereon upon which said sheetsare formed in a thin and evenly-distributed film, as and for thepurposes set forth.

2. The herein-described apparatus for the manufacture of thin sheets ofnitrocellulose or pyroxyline, which consists of a suitable tank providedwith means for drawing the solution therefrom and a spirally-formedplate or coil upon which said sheets are formed in a thin andevenly-distributed film, as and for the purposes set forth.

In testimony that I claim the invention set forth above I have hereuntoset my hand this 10th day of November, 1890.

EDMUND N. TODD.

Witnesses:

FREDK. C. FRAENTZEL, WM. H. OANFIELD, Jr.

